Hoisting mechanism



Jully Q, 1924},

1,499,613 C.HAYES H01 STING MECHANISM Filed April 27. 192] Patented .luly l, l924.

CHARLES HAYES, or BROOKLYN, new YoRn, AssIe1\ToaTo GILLis & enoennean,

- rim, or new YORKMN. A. conronATIon on NEW YORK.

norsrine MECHANISM.

Application filed April 27, 1921 Serial No. 464,905.

To all whom it may concern:

Be it known that I, CI-IARLEs IIAYESVQ, citizen of the United States, residing in the city of New York, borough of Brooklyn, in the county of Kings and State of New York, have invented a certain new and useful Improvement in Hoisting Mechanism, of which the following is a specification.

' The invention relates to electrically operated hoisting machines and more especially to machines adapted for raising ash cans and like light loads in sidewalk hoistways.

The present invention is based on the structure shown and described in Letters Patent of the United States, granted to Joseph H. Donat for an improvement in hoisting mechanism, dated March 9, 1920, No. 1,333,064, in which the-hoisting, lowering, and braking operations are all controlled by a single operating-lever swung to corresponding positions, and the brake actuated by a spring of suflicient tension to support and hold the load suspended when the hoisting mechanism is idle.

The object of the present invention is to provide means auxiliary to the spring for temporarily increasing the brake action, es-' pecially at the beginning of the hoisting effort; thus overcoming the initial resistance due to the inertia of th load, and avoiding the necessity of maintaining an unduly high spring tension.

Another important ob ect is to provide simple means whereby the increased brake action is automatically effected by the movement of the operating-lever to the hoisting position.

The invention consists in certain details of construction and arrangement by which the above objects are attained to be hereinafter described and claimed.

The accompanying drawings form a part of this specification and show the invention as it has been carried out in practice.

Figure 1 is a plan view of a hoisting head, with the main portions of the electric motor omitted, and showing a preferred form of the improvement.

' Figure 2 is a corresponding side elevation, partly in vertical section.

Figure 3 is a plan view of the brake-lever alone.

Figure 4 is a transverse section through the brake-lever, taken on the line 44 in Figure 3, showing the operating fingers in dotted lines.

Referring to the drawings, the frame of the hoisting head is marked 1, and 2 and 3 indicate the operating-shaft and hoisting shaft respectively, the latter being equipped with a hoisting-drum 4, differential gear 5 and a brake-drum 6 operated in a manner analogous to that set forth in Letters Patent No. 1,333,064, above referred to, in which the tightening of the brake-band 7 conditions the differential gear to hoist the load, and its release allows the load to lower by gravity.

A brake-lever 8 fulcrumed to the frame at 9 carries the brake-band, as shown in F igure 2, and is arranged to apply the brake by a depression of its free end, which depres sion is normally effected by a contractile helical spring 10 attached at oneend to the brake-lever and at the other to 2. depending bracket 11 on the frame.

On the overhung end of the operating shaft 2 is a sleeve 12 jointed to the operatingshaft by a clutch at l3,and equipped with an operating-lever 14 and an arm '15. The latter through a link 16 and crank arm 17 controls a switch, not shown, in the switchbox 18 of the motor 19, so arranged that a movement of the operating-lever 14 to the right in Figure 2 energizes the motor and revolves the hoisting shaft 3 in the direction to hoist the load.

, At the opposite end of the operating shaft 2, within the head, is fixed a boss 20 having radially extended fingers 21 inclosing the brake-lever 8 between them and adapted to contact with the lugs 22 011 the brake-lever and lift the latterwhen the operating-lever is swung to the left in Figure 2. Thus conditioned the current is out OK, the brake re leased, and the hoisting shaft freed to permit the load to descend at a rate controlled by the operator through the operating-shaft 2 and its fingers 21 acting upon the lugs 22 of the brake-lever in opposition to the force of the spring 10.

The tension of the spring 10 must be sufficient to hold the brake and sustain the load during the hoisting operation when the operating-lever is thrown to the right, as above described, and also to sustain the load when the operating-lever is in the middle or neutral position, as represented in the drawings. It has been found by experiment that a relatively light tension will suffice for these conditions, and as it is evident that the force required to be exerted by the operator in raising the brake-lever to release the brake must exceed the force exerted by the spring, it is desirable to adjust the spring to as low tension as is practicable; but it is found that in overcoming the inertia of the load in initiating the hoisting movement a much greater spring tension is required to insure the grip of the brake band, and as the tension of the spring is constant the operator must work against an abnormally and unnecessarily great resistance in the releasing operation.

To overcome this disadvantage the brakelever 8 is equipped with a cam 23having a surface eccentric to the are described by the fingers 21 in their oscillations and so disposed as to be struck by the ends of the fingers in their swing and thus aid the spring 10 in depressing the brake-lever and correspondingly increasing the grip of the brake-band when the lever is thrown to the right in starting the motor and initiating the hoisting operation, and also during the hoisting operation if desired, relying upon the spring alone to maintain the load when the operating-lever is in the neutral position.

The eccentricity of the cam surface is preferably slight, thus rendering the device sensitive and enabling the operator to control and vary the tension with slight effort.

Modifications may be made in applying the invention to other forms of hoisting apparatus, and other means than the fingers 21 and cam 23 may be employed in effecting the movement of the brake-lever as an auxiliary to a spring, or its equivalent, exerting a constant brake tension.

I claim:

1. In a mechanism of the character set forth, a brake lever arranged to apply a brake by exerting a normally constant tension thereon, an arcuate surface on said lever, an operating lever, and means mounted on the shaft of said operating lever and cooperable with said arcuate surface.

2. In a mechanism of the character set forth, a brake-lever having an arcuate surface and arranged to apply a brake by means exerting a normally constant tension thereon, an operating-shaft and means for moving it, and means actuated by said shaft movable in a path eccentric to said surface and acting upon said lever for increasing and varying such tension.

3. In a mechanism of the character set forth, a brake-lever arranged to apply a brake by means exerting a normally constant tension thereon and carrying a cam, an operating-shaft and means for moving it, and means carried on said shaft movable in a path concentric to said cam and arranged to co-act with the cam on said lever for increasing and varying such tension.

4. In a mechanism of the character set forth, a brake-lever arranged to apply a brake by means exerting a normally constant tension thereon, a cam on said lever, an operating-shaft and means for moving it, and a finger on said shaft movable in a path concentric to said cam arranged to co-act with said cam on said lever for increasing and varying such tension.

5. In a mechanism of the character set forth, a brake-lever having a cam, a spring acting on said lever to apply a brake, an operating-shaft and means for moving it, and a finger on said shaft movable in a path concentric to said cam arranged to contact with said cam and aid said spring in applying such brake.

6. In a mechanism of the character set forth, a brake-lever having a cam and lugs thereon, a spring acting on said lever to apply a brake, an operating-shaft and means for moving it, and a finger on said shaft movable in a path concentric to said cam and arranged in one position of said shaft to contact with said lugs and move said lever in opposition to said spring to release such brake, and in another position to contact with said cam and aid said spring in applying such brake.

In testimony that I claim the invention above set forth I affix my signature.

CHARLES HAYES. 

